The present invention relates to a strap assembly for attachment to portable devices such as game units, telephones, pagers, cameras and power packs.
Prior art for this kind of strap assembly has been disclosed in many publications, including Japanese Kokai (laid open patent applications) numbered H8-103320, H8-154725, H8-196325, H10-57121 and H10-276920.
These prior inventions added improvements in a variety of areas such as ease of manufacturing, cost of manufacturing, and ease of attachment and removal of the strap assemblies. It is important to note, however, that in all of these disclosures, as a basic requirement, special importance was placed on the reliability of the strap assembly in terms of its ability to remain securely attached to the portable item when subjected to a large pulling force.
For preventing loss of the portable unit, a strap assembly must of course maintain a given level of pull strength. However for safety reasons further increasing the pull strength of the strap assembly does not necessarily mean better quality. For instance, if the portable unit were to be inadvertently caught on nearby structures or forcefully snatched from the user in a theft attempt, it would be better to have a strap assembly that would break away from the unit when subjected to sudden unexpected external force.
Especially in strap assemblies intended for use with portables such as the popular portable game units for which there is a strong demand among the very young, greater importance should be placed on the safety of the user than on the loss of property.
In view of consideration of the safety of users of strap assemblies it is an object of the present invention to protect the user from injury in case a sudden unexpected external force is applied.
To accomplish the above and other objects, a strap assembly of the present invention is configured to separate from the portable unit when the portable unit is subjected to a tension load in excess of a given level. The present invention is suitable for application in a variety of strap assemblies. For example, a strap assembly having a belt-shaped strap that is coupled to a portable device though a coupling unit may be made such that at least the strap will separate from the portable device when the portable device is subjected to a tension load in excess of a given level.
In addition, in the configuration described above, if the assembly is constituted of a coupling for coupling a cord installed on a portable device to the strap, the coupling may comprise a coupling release means for separating the strap when the portable device is subjected to a tension load in excess of a given level.
Accordingly, when the portable device is subjected to an unexpected external force (pulling force), a strap hanging from the body of the user will be pulled away from the coupling, thus preventing the user from being restrained by external force.
Also the present invention may be configured such that the coupling comprises a first coupling member and a second coupling member that cooperate with one another to maintain a coupled state of the strap; the coupling members maintain the coupled state of the strap through the mating of a protrusion formed in one of the members with a recess formed in the other of the members. The protrusion and recess also function as a coupling release means for releasing a mated state thereof to separate the strap based on the action, on the portable device, of a tension load in excess of a given level.
When the configuration of the present invention is used, the assembly can be made so that the components are not damaged during separation. This provides an advantage in terms of economy in that the assembly can be restored to use after simply re-engaging the protrusion and recess.
The present invention may also be configured so that the strap forcefully separates from the body of the user when the portable unit is subjected to a tension load in excess of a given level. The separation from the body referred to here is not the kind of separation that occurs, for example when the strap suddenly comes off the wrist: it is a separation from the body accompanied by actual structural deformation of the strap itself, due to the portable device being subjected to a tension load in excess of a given level.
In the above configurations of the present invention, when making determinations as to the action, on the portable device, of a xe2x80x98tension load in excess of a given levelxe2x80x99 it is desirable to consider a variety of factors from the standpoint of ensuring the safety of the user. These factors should include, for example, the part of the body from which the portable device is suspended, the area and width of the component of the strap assembly that is in contact with the body (e.g. the strap), and the age of the user.
As a result of experiments conducted by the inventors up to this point, wherein it was a precondition that the portable item be hung around the neck or wrist of the user""s body, it was found that it was desirable in terms of ensuring the safety of user for when the portable device was subjected to a tension load of 7 kg or more (i.e., when the xe2x80x98given level of tension loadxe2x80x99 was set to 7 kg or more.